From mboxrd@z Thu Jan 1 00:00:00 1970 From: gprabhunath@gmail.com (Prabhu nath) Date: Wed, 27 Apr 2011 10:03:47 +0530 Subject: VMA of processes and CPU registers In-Reply-To: <201104252208.57103.mindentropy@gmail.com> References: <201104202133.39612.mindentropy@gmail.com> <201104252208.57103.mindentropy@gmail.com> Message-ID: To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org My Apologies for top posting. Now in continuation to my previous question. Is there a method to know whether segmentation unit is enabled or disabled either from Kernel space or user space. Thanks, Prabhu On Mon, Apr 25, 2011 at 10:08 PM, mindentropy wrote: > On Monday 25 Apr 2011 2:25:10 pm Prabhu nath wrote: > > I understand about Linear virtual address and Physical address. How is > the > > logical address generated ? Can you please explain. > > > > Thanks, > > Prabhu > > > > On Wed, Apr 20, 2011 at 9:33 PM, mindentropy > wrote: > > > On Wednesday 20 Apr 2011 4:31:08 pm limp wrote: > > > > Thanks a lot Dace and Vladimir for your replies. > > > > > > > > First of all, I forgot to mention that I am talking for x86 > > > > architecture. > > > > > > > > > The CPU registers will contain the virtual addresses. Each and > every > > > > > time that the CPU tries to access a virtual memory location, then > the > > > > > address will be translated by the MMU into a physical address. > > > > > > > > So, AFAIU the translation to physical memory takes place *only* when > > > > the ALU of the processor has to do some operation which has memory > > > > operands (in this case the CPU needs to deal with the *real* > > > > addresses) but not prior to that. > > > > > > The address translation happens in the following way: > > > > > > Logical Addr-->|Segmentation Unit|-->Linear Addr -->|Paging unit|--> > > > Physical > > > Addr. > > > > > > If the paging unit is not setup then the linear addr is the physical > > > addr. > > > > > > _______________________________________________ > > > Kernelnewbies mailing list > > > Kernelnewbies at kernelnewbies.org > > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > In the segmented memory model the memory appears as segments. In this model > the program issues a logical address which comprises of a segment:offset > address. The offset selects a byte in the segment. The segmentation unit > converts it to a linear address. If the paging unit is enabled the linear > address passes through the paging unit for further translation. > > > Also please do not top post :) > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110427/b70119fa/attachment-0001.html